Fix issue with filtering where a value is unicode.
Fix issue with filtering where a value is unicode.

This fixes an issue where if an attribute, such as name, for an instance
contains unicode and doing a list of instances filtering by that attribute
causes a 500 error.

fixes bug 1031846

Change-Id: I2e9e9a36194dad1326b0d7257308576f8553ef06

n0ano/gantt,n0ano/gantt